New Clothes Dryer

[penzman]

I'm no electrician and thought someone may see what the problem is here.

We've just bought a new clothes dryer to avoid having our clothes being ironed until they're as shiny as glass

Works great!.. for a while. One of the breakers keeps tripping.

See the picture below. The dryer trips breaker #4.

The only oher things that run on the same breaker are the tv and a few lights. Water pump and aircon are on another breaker and were not running at the time.

Can anyone tell what's wrong and what to change in the box in order to stop this?

Thanks,

Penzman

[davethailand]

Run it on a 32amp breaker, 16 is too small for that and the water pump, tv etc.

[loong]

If it is a 16 amp breaker, then that should be okay for a total load of around 3.5Kw.

If your drier rating exceeds this, then you will get this problem.

Check with the shop that sold you the drier

Is the wiring to the drier and / or socket getting hot? Wiring standards are not that great in Los.

Edited September 12, 2005 by loong

[lopburi3]

As said 16 amp is far too small for a dryer which is probably rated at 4,000 or 5,000 watts. You might be able to use a 16 amp for one of the air conditioners in position one or two: but not for a dryer.

[chownah]

SORRY FOR THE CAPS BUT THIS IS IMPORTANT, do not just take out the 16 amp breaker and replace it with a larger one. A larger breaker means that all the wires that connect to it must be upgraded to handle the amperage of the breaker. In theory it is possible that they wired the 16 amp breaker with oversized wires but it is highly unlikely. To do it right you must replace ALL wire which is activiated by the breaker with wire big enough...this will be a problem because many light fixtures have such small connecting hardware that the larger guage wires won't even fit in. I guess I'll stop my explanation here since you said you are not an electrician so I guess you'll hire one!

[davethailand]

SORRY FOR THE CAPS BUT THIS IS IMPORTANT, do not just take out the 16 amp breaker and replace it with a larger one.  A larger breaker means that all the wires that connect to it must be upgraded to handle the amperage of the breaker.  In theory it is possible that they wired the 16 amp breaker with oversized wires but it is highly unlikely.  To do it right you must replace ALL wire which is activiated by the breaker with wire big enough...this will be a problem because many light fixtures have such small connecting hardware that the larger guage wires won't even fit in.  I guess I'll stop my explanation here since you said you are not an electrician so I guess you'll hire one!

<{POST_SNAPBACK}>

2.5mm minimum for the drier i believe (and TV's, power outlets)

[penzman]

I ll switch off the power tomorrow and climb up the attic/sauna and see how they laid out the spaghetti.

I l check and see if the wiring gets hot afterwards.

The drier is grounded and connected to a safe t cut which gets it's juice from a wall outlet that does have a ground ( I instaled the outlet).

Should the safe t cut have jumped before the house breaker did?

[loong]

The drier is grounded and connected to a safe t cut  which gets it's juice from a wall outlet that does have a ground ( I instaled the outlet).

Should the safe t cut have jumped before the house breaker did?

<{POST_SNAPBACK}>

As far as I understand, the main breaker will trip due to overloading the circuit. A safety breaker is normally of the earth leakage type. So if there is no earth leakage the safety breaker will not trip. The safety basically measures the power in the 2 wires and if there is a difference outside of the set range, it will trip. Ie if power is travelling down one wire and then to ground instead of to the other wire, then it will be detected and the power is cut.

[davethailand]

Penz, if the wires into the 16amp breaker are 2,5 mm (even 2mm if not always on) then just put in a 32a breaker.

[lopburi3]

You did not have a ground fault but too much current being drawn and that little 16 amp breaker on your panel I suspect is much lower than the rating of your Safe-T-Cut breaker/GFI. So the lower rated breaker will trip first.

[Crossy]

This is a table from BS6500 which is reproduced in the IEE Wiring Regs which describes the maximum fuse sizes for different conductor sizes:

Cross- Overload

sectional current

area rating

0.5mm² 3A

0.75mm² 6A

1mm² 10A

1.25mm² 13A

1.5mm² 16A

Typical current ratings for mains wiring

Inside wall

mm^2 A

1.5 10

2.5 16

I don't think I'd put a 32A breaker on 2.5mm cable, 25A would be more sensible.

Check the rating plate on the dryer, if you're lucky it will have Amps, otherwise take the Watts figure and divide by 220 to get amps. I'll bet it's 3kW (3000W) thats about 14A, a bit near for a 16A breaker.

Time to get out the 25A unit (assuming you have 2.5mm cable of course).

[lopburi3]

From a quick Google see that UK allows 27 amp fuse for 2.5mm open wire (as most is here - in insulated wall it drops to 18 amps) so your 25 suggestion is probably in line with that (but may not be available here).

As for dryers my unit (export American model bought here) specifies a fuse of 30 amps. They are really big electric users and should be wired directly to breaker. Don't recall wire size but know it was larger than 2.5 which have used for everything else. Believe it may have been 4mm.

[Crossy]

So it's down to Penzman to let us know the rating of his dryer

Interesting about US standard dryers, in the UK a domestic dryer is no more than 3kW (domestic outlets are 13A 240V). A 4-5kW unit is most definately 'industrial strength'.

[chownah]

I've been doing some googling too and am a bit confused about the designation on Thai wiring. For wire size it shows on the wire something like "2.5 SQ. MM.". Can someone tell me what this means? I've got an aluminum seven strand cable leading to my house and it says "25 SQ. MM." The seven strand bundle (excluding the insulation) measures about 7 millimetres in diameter.....using pi x r x r gives a cross section area of about 38 so it seems that the cross section of the actual conductor (not including the empty space between the strands) would be about 25 square millimeters.

Is a 2.5 SQ. MM. wire a wire with 2.5 square millimeters of cross section?

[Tywais]

I've been doing some googling too and am a bit confused about the designation on Thai wiring.  For wire size it shows on the wire something like "2.5 SQ. MM.".  Can someone tell me what this means?  I've got an aluminum seven strand cable leading to my house and it says "25 SQ. MM."  The seven strand bundle (excluding the insulation) measures about 7 millimetres in diameter.....using pi x r x r gives a cross section area of about 38 so it seems that the cross section of the actual conductor (not including the empty space between the strands) would be about 25 square millimeters.

Is a 2.5 SQ. MM. wire a wire with 2.5 square millimeters of cross section?

They put the decimal in the wrong place or added "SQ" incorrectly (mislabeling in Thailand is not uncommon) otherwise you are talking about a wire size of .9 mm or 900um, human hair is about 150um. sqr(2.5/pi)

[lopburi3]

So it's down to Penzman to let us know the rating of his dryer

Interesting about US standard dryers, in the UK a domestic dryer is no more than 3kW (domestic outlets are 13A 240V). A 4-5kW unit is most definately 'industrial strength'.

<{POST_SNAPBACK}>

American size, as usual, is much larger and heaters alone often draw more than 5 kw.

[Tywais]

Also the running current and the startup current are not the same. Could be an inrush surge as the motor starts up that trips the breaker. Since you have 32amp breakers might check and see what is on them and move the dryer to one of these breakers.

Just looked at your picture, you have an airconditioner and hot water heater on the 32amps. Might connect the dryer to one of these and not run the air and hot water heater when drying clothes.

Edited September 14, 2005 by tywais

[penzman]

So it's down to Penzman to let us know the rating of his dryer

Interesting about US standard dryers, in the UK a domestic dryer is no more than 3kW (domestic outlets are 13A 240V). A 4-5kW unit is most definately 'industrial strength'.

<{POST_SNAPBACK}>

10.1KG dryer. American Brand.

Volts: 220-240V

Frequency& Phase: 50HZ (1 phase 2 wire)

Type&Size of Circuit: No.10 AWG Copper

Fuse Size : 30 AMP

Says 4.5 KW on back of the dryer.

[chownah]

So it's down to Penzman to let us know the rating of his dryer

Interesting about US standard dryers, in the UK a domestic dryer is no more than 3kW (domestic outlets are 13A 240V). A 4-5kW unit is most definately 'industrial strength'.

<{POST_SNAPBACK}>

10.1KG dryer. American Brand.

Volts: 220-240V

Frequency& Phase: 50HZ (1 phase 2 wire)

Type&Size of Circuit: No.10 AWG Copper

Fuse Size : 30 AMP

Says 4.5 KW on back of the dryer.

<{POST_SNAPBACK}>

Now we're getting somewhere....definitely a 30 amp circuit in America requires a No. 10 AWG copper wire...I know this from personal experience....the problem for me is to figure out which wire this will be in Thailand....every where on the net I find the same information:

No. 10 AWG = 0.1019 inch diameter = 2.588 mm diameter. The problem is that the metric measurement is in millimeters of diameter...NOT in square millimeters. I've been measuring wire and calculating on this and haven't yet come up with the answer.

For example...I've got some cable that is marked "2x1.5 SQ. MM.". I don't have a good set of calipers or a micrometer but I'm pretty good at eyeballing with a ruler and when I measure one of the wires in this two wire bundle it measures really close to one millimeter in diameter....the simple math gives a cross sectional area of 0.5x0.5xpi=0.785 square millimeters....doesn't make sense to me...I'm going to keep working on this....can anyone help me out?...am I missing something? I'm going to see if I can refine the accuracy by which I measure the 1.5 SQ.MM. wire and also see if I can find a scrap of other sizes.

[ProThaiExpat]

I checked with my Whirlpool Super Capacity Dryer and just inside the door is a sticker that indicates it is 15 Amp rated.

I checked with my "fuse box" and the "circuit breaker" for the washer and dryer closet is rated at 20 amps. I have never had a problem to date, three years now.

If you can locate the amperage rating for your dryer, either on the machine itself or in your operating manual accompaning it, you can determine its rating and if your circuit braker is rated equal to or greater than the dryer, your problem is not an overloaded circuit but a short in the line or in the dryer or undercapacity wiring.

You might find a rating plate for the dryer on the back of the dryer. I like the post that suggests you move the wiring serving your dryer in your circuit breaker box to a circuit breaker rated higher, to see if it is a underated circuit breaker problem.

If not, short circuit in the wiring, in the appliance or inadequat power into the house may be the problem. Turning off all "resistence" demand appliances to test incoming power adequancy, previously suggested, is a must. You probably already know that next to an electric stove, the dryer and your water heaters require the most electricity to operate.

Good luck in finding the problem.

[lopburi3]

This http://www.mogami.com/e/cad/wire-gauge.html will convert between various measurements. 2.5sq mm would be size 14 AWG.

Americans (where 12 AWG is normal) may think that small but remember we are talking 220 volts rather than the 120 in the USA so a much smaller wire can carry the same power.

[chownah]

I've got a 32 amp circuit in my house for an electric water heater....and its got 6 SQ.MM. wire....I also talked to my uncle who did the wiring in my house and has a history of working as an electrician in Bangkok years ago and asked him what size to use for a 32 amp breaker and he answered that it takes a number 6..and that this is the way most people do it and it is also the way the engineers do it in Bangkok. If I were you I would go look at the wire that comes from the 32 amp breaker existing in your house and see what size wire is connected to it....if its less than a 6 SQ.MM. then I'd check out all the rest of the wiring to see if it is substandard too. In the US all of the wire on every part of every circuit that connects to a breaker must be big enough for that breaker...if you are running an 8 watt light off of a 32 amp breaker then you need to have 6 SQ.MM. wire running all the way to the light. I have seen circuits in Thailand that start off from the breaker the right size but then are reduced in size at the first junction....this is not allowed in the US and is not the best safety practice.

As to interpretting the metric wire size...I have remeasured the 1.5 SQ.MM. wire and it is bigger than I thought....I'm beginning to think that in fact the SQ.MM. measurement is the cross sectional area of the actual metal conductor itself. For example the 6SQ.MM. wire used for a 32 amp circuit would have a diameter of 2.76 millimeters (by mathematical calculations). When I measured my 6SQ.MM. wire in my house it looked to be more than 2.5 and less than 3 millimeters...so it matches with the calculated diameter..... and also this is a little bit bigger than the 2.588millimeter wire that is used in the US for the 30 amp circuit.

[chownah]

This http://www.mogami.com/e/cad/wire-gauge.html will convert between various measurements.  2.5sq mm would be size 14 AWG. 

Americans (where 12 AWG is normal) may think that small but remember we are talking 220 volts rather than the 120 in the USA so a much smaller wire can carry the same power.

<{POST_SNAPBACK}>

My calcs show the same....14 AWG = 1.63 mm diameter = 2.09 sq.mm.

In the US a 14 AWG wire meets code for a 15 amp circuit....in Thailand they have 16 amp circuits so clearly a 2 SQ.MM. wire is a bit too small...use the 2.5 SQ.MM. for a 16 amp circuit.

Also, I believe that the voltage makes no difference in the wire size....in the US code the wire sizes don't change for 110 or 220 volts.

[lopburi3]

This http://www.mogami.com/e/cad/wire-gauge.html will convert between various measurements.  2.5sq mm would be size 14 AWG. 

Americans (where 12 AWG is normal) may think that small but remember we are talking 220 volts rather than the 120 in the USA so a much smaller wire can carry the same power.

<{POST_SNAPBACK}>

My calcs show the same....14 AWG = 1.63 mm diameter = 2.09 sq.mm.

In the US a 14 AWG wire meets code for a 15 amp circuit....in Thailand they have 16 amp circuits so clearly a 2 SQ.MM. wire is a bit too small...use the 2.5 SQ.MM. for a 16 amp circuit.

Also, I believe that the voltage makes no difference in the wire size....in the US code the wire sizes don't change for 110 or 220 volts.

<{POST_SNAPBACK}>

The wire size difference is in the power (VA - almost the same as watts) that it can supply. 220v x 15a = 3,300 VA but at 120v x 15a = 1,800 VA so you have dropped from being able to run a normal size on demand water heater here using 220v to only enough to power a strong hair dryer at 120v.

Also why you can run a house with 45 amp service here where in the US you would probably want 100 amp service.

You are thinking the same size wire carries the same number of amps but when you increase the voltage those amps give you a much higher wattage to use.

Edited September 14, 2005 by lopburi3

[Crossy]

So it's down to Penzman to let us know the rating of his dryer

Interesting about US standard dryers, in the UK a domestic dryer is no more than 3kW (domestic outlets are 13A 240V). A 4-5kW unit is most definately 'industrial strength'.

10.1KG dryer. American Brand.

Volts: 220-240V

Frequency& Phase: 50HZ (1 phase 2 wire)

Type&Size of Circuit: No.10 AWG Copper

Fuse Size : 30 AMP

Says 4.5 KW on back of the dryer.

Ah-ha, a big beastie. Explaines why your little 16A breaker is going out, poor thing

You need a seperate circuit with a 32A breaker and 4 mm^2 wire. Talk to your friendly local electrician, looks like you've room in the consumer unit for another breaker, should be a cinch to install.

Your main breaker is only 45A so you may get trips if you run the dryer and aircon / kettle together.

Edited September 14, 2005 by Crossy

[penzman]

Then it's a seperate circuit with a 32A breaker and 4 mm^2 wire dedicated to the washer and dryer only.

Should I also increase the main breaker from 45A to something a little higher?

[simcity]

That is perhaps stupid what I am saying! And perhaps not same problem!

When I got my dryer, it trip and the guy put the hearth on a extension to the ground..

Working fine 6 years later .

[Crossy]

Then it's a seperate circuit with a 32A breaker and 4 mm^2 wire dedicated to the washer and dryer only.

Should I also increase the main breaker from 45A to something a little higher?

I'd suck it and see, if you increase the main you may be required to get a bigger meter / supply by the electricity authority.

Ask the advice of your electrician who puts in the new breaker and cabling.

In Italy my place had a 15Amp INCOMMING supply, judicious timing of water heater / aircon / washer / kettle / iron was required, any two of those on together would take out the breaker, your dryer would have blown it into next week.

[lopburi3]

It that your only breaker panel? Most homes will have a dedicated breaker for incoming feed and run panel off of that.

They seem to use 60 amp main breakers even on the normal 15/45 amp meters. Don't ask - I don't know why. Perhaps they assume any overload with be short term and caused by air conditioner start up? In any case I would assume/hope the main feed could safely carry 60 amps.

I would install another 32 amp breaker for just dryer and heavy wire between panel and dryer (do not use a outlet/plug but wire direct) and when you are using dryer remember not to use water heaters. You may be able to run a/c but if main breaker trips, maybe not. In our house dryer is seldom used as everyone prefers sun dry when possible (and have 10 in family so there is a lot).

The washer should not be a problem as they do not draw very much power compared with a dryer.

[penzman]

Meter on electric pole is 15-45 A.

I won't bother replacing the main breaker, just run a new heavier cable from newly added 32A breaker.